// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_LOCKED_QUEUE_H_
#define V8_LOCKED_QUEUE_H_

#include "src/allocation.h"
#include "src/base/platform/platform.h"

namespace v8 {
namespace internal {

    // Simple lock-based unbounded size queue (multi producer; multi consumer) based
    // on "Simple, Fast, and Practical Non-Blocking and Blocking Concurrent Queue
    // Algorithms" by M. Scott and M. Michael.
    // See:
    // https://www.cs.rochester.edu/research/synchronization/pseudocode/queues.html
    template <typename Record>
    class LockedQueue final {
    public:
        inline LockedQueue();
        inline ~LockedQueue();
        inline void Enqueue(const Record& record);
        inline bool Dequeue(Record* record);
        inline bool IsEmpty() const;
        inline bool Peek(Record* record) const;

    private:
        struct Node;

        mutable base::Mutex head_mutex_;
        base::Mutex tail_mutex_;
        Node* head_;
        Node* tail_;

        DISALLOW_COPY_AND_ASSIGN(LockedQueue);
    };

} // namespace internal
} // namespace v8

#endif // V8_LOCKED_QUEUE_H_
